<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      div {
        width: 200px;
        height: 200px;
        /* border-width: 5px;
         border-style: 边框样式 solid 为实线边框  dashed 为虚线边框 dotted为点线边框
        border-style: dotted;
        border-color: pink; */
        border: 5px solid blue;
        border-top: 5px solid red;
        border-bottom: 10px dashed blue;
      }
    </style>
  </head>
  <body>
    <!-- border边框 content内容 padding内边距 margin外边距 -->
    <div></div>
  </body>
</html>
